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Forest Adaptation Resources for Addressing Climate Change Tools and Approaches for Land Managers

Posted: June 17, 2014

Careful stewardship of woodlands and forests is an involved task, especially if you strive to build resistance and resilience into your management goals and to be prepared to respond to change. The ten strategies offered in "Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers" are logical and provide a solid foundation for developing short- and long-term plans for caring for your woodlands and the values you attribute to the land.

By Jim Finley, Ibberson Professor of Forest Management, Penn State Department of Ecosystem Science and Management

A week or so ago I picked up one of the many forestry and natural resource focused magazines and newsletters that come to the office. One article with a title similar to this article caught my eye. It was a report of a Vermont workshop for professional foresters designed to help them adapt forest management approaches to forest conditions attributed to climate change. The workshop used a USDA Forest Service publication, Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers.

While the publication focuses on northern Wisconsin forests, I wanted to see how their perspective might fit Pennsylvania. As well, I wondered about approaches that would help woodland owners think about how to care for their properties as they experience change – climate driven or otherwise. The authors are careful to acknowledge that their recommendations are not prescriptive; rather, they are broad and conceptual. They offered that because forests are diverse biological systems and projections related to climate change are not precise, it is nearly impossible to define concrete approaches. Second, related to these reasons, many of their scenarios extend to other forests and conditions – they are not constrained to Wisconsin. Third, the publication is written for managers working in partnership with others to affect large landscapes; nonetheless, it suggests strategies that warrant consideration by anyone interacting with forests. Finally, they suggest that careful managers, through their stewardship practices, are already implementing and observing many of their suggested approaches. I strongly agree with this last point

Adapting forests to climate change, or almost any change for that matter, is not easy. Change is a natural forest process – forests are dynamic; however, the rate of change is normally relatively slow. More rapid change is attributable to weather (e.g., drought, wind, ice) and human causes (e.g., harvesting, planting, introduced insects, and diseases). To “help” forests through these challenges it is useful to consider how we can use an understanding of resistance, resilience, and response to create adaptive approaches.

Resistance is about improving a forest’s defenses to change, defending directly against change (e.g., spraying for insects), or protecting from disturbance (e.g., buffering against wind penetration by leaving trees on the windward side of a stand). Resilience allows for a level of change, but strives to return the forest to an initial condition. It might involve reducing forest density to increase residual tree vigor with the intent of allowing the stand to recover. Response is about accepting change and moving the stand to some different future condition (e.g., shifting species composition, artificially increasing species diversity). Beyond climate change, all forest management decisions involve some level of building resistance, resilience, and response into our actions.

Without further clarification and depending on your past experience with your woodlot, you might have some ideas about what each of these suggests. Strategy 1 is about keeping the forest system healthy and functioning as water and soil conditions change. Maybe we’ll get more rain that limits logging chances, or in some areas less rain, which changes soil hydrology and causes wetland species to struggle. This strategy addresses the need to care for site productivity and sensitive areas such as wetlands or riparian areas that benefit from tree, especially conifer, cover. Strategy 2 calls for anticipating changing conditions to reduce stress on forest functions. An appropriate response might involve changing stand density, structure, or composition. For example, it might be wise to reduce stocking of one species threatened by insects or diseases to improve conditions for another species. Or, you might have plan in place to address existing or expected invasive plant species that stress regeneration. Similarly, understanding the impact of deer or other herbivores, you could take steps to reduce their impact on species diversity and regeneration.

Fire, wind, and ice (Strategy 3) are variously common in Pennsylvania’s woodlands. In the future, occurrence of these management challenges might change across the forest. Depending on local weather and vegetation patterns, the impacts of fire, wind, and ice may change. It might be prudent to use prescribed fire to increase resilience in some areas; it might be wise to reduce trees susceptible to wind and ice damage in other sites. Regardless of the type of disturbance, a goal is to respond to encourage recovery. Strategy 4, Refugia, is about identifying, protecting, and retaining ecosystems or communities at risk in the larger landscape as change happens. It might be that the refugia are a reserve or a place where active management has to happen to create or maintain desired conditions. It is important to assess the stability of refugia – are they protected, isolated, or easily maintained? In the context of climate change, refugia might involve creating places to protect and propagate species from southern areas that will eventually do better in more northern climes.

We talk frequently about maintaining and enhancing species and structural diversity (Strategy 5) in our education programs and writings. By recognizing the susceptibility of some parts of a system, diversity provides a buffer against change. This strategy seems most developed and easily grasped. In our forests, promote diverse age classes. Diverse forests of native species are likely more resilient to change even with the loss of some species. All management activities should strive to maintain or maybe even increase native species diversity. This relates to the idea of biological legacies – species that somehow remain in an otherwise changed landscape. That unique species is fundamentally important and may represent a genetic pool that can adapt to future conditions. Think about that surviving beech tree after the killing front of beech-bark disease, or the hemlock that manages to hang on after the hemlock wooly adelgid. This strategy also relates well to the idea of refugia – protect ecosystem diversity

Strategy 6 champions redundancy across landscapes. As we experience change, some habitats are going to respond better than others. Having a complex of plants and animals scattered across the landscape is going to help ensure that some examples of existing conditions remain as others undergo too much change. Of course, in some ways, bigger areas are more likely to contain the exceptions that will continue. This, too, relates to reserves and refugia – the bigger the better. Retaining examples, even small ones, are important. We all live within a landscape, and Strategy 7 addresses the need to provide connections. Regardless of what we might expect in the future, we need to connect patches in our fragmented landscapes. This will help species migrate as they adjust to changing conditions. This, however, is a double edged sword. Connections benefit many undesirable stressor species also, which implies the need to identify and control exotic invasive species. It is also important to consider that some desirable species might not have the capacity to move rapidly and we might have to be aware of the need to facilitate their advancement into new habitats.

Enhancing genetic diversity (Strategy 8) embraces several other strategies and may require more sophisticated knowledge and tools to evaluate, select, protect, and propagate genetic material. Fortunately, the scientific community is already looking at some of these issues and has the capacity to design and maintain systems to capture some of the genetic diversity. As a landowner or manager, you can help by identifying and protecting legacy species. Strategy 9 is about facilitating community adjustments as species change. With climate change, some species in any grouping of species are going to come or go at different rates, so forest types (e.g., oak/hickory, beech/birch/sugar maple) are not going remain the same. In this process, some niches are going to become open and it might be necessary to adjust management or actions to fill these voids with appropriate alternatives. An example today in Pennsylvania is the loss of eastern hemlock in riparian areas. What species should we suggest? What species will fill that void? Some are suggesting non-native spruce; another alternative is eastern white pine. Neither is the same as hemlock, what are the best choices? The strategy argues for selecting native over exotic.

Finally, Strategy 10 is about understanding that change is going to happen. In the publication they suggest that the best opportunity to respond is immediately after a disturbance (e.g., fire, wind, or ice); however, with regeneration and competitive plants, both native and exotic, perhaps the best opportunity is before change occurs. Forest management and regeneration is a process, not an event. So, the astute manager or steward is aware of pending change and is building resilience into the system. Climate change may bring more frequent or more severe disturbance events, or we might experience more or less rain or higher peak temperatures; it will be difficult to predict with our current knowledge.

Careful stewardship of woodlands and forests is an involved task, especially if you strive to build resistance and resilience into your management goals and to be prepared to respond to change. The ten strategies offered in this publication are logical and provide a solid foundation for developing short- and long-term plans for caring for your woodlands and the values you attribute to the land. As you work with your land, your resource professional, and even your family, think about how you can make sure that your decisions lead to sustainable outcomes. Sustainable forestry is about retaining options as you care for the land today and consider how those who follow you will care for the land, too.

Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers is available on line at http://www.nrs.fs.fed.us/pubs/40543 as a pdf. It contains much useful information and food for thought. Give it a look. I’ve only hit on the high points here.